The structures that abut the cranial and peripheral surfaces of the temporal bone are of no little import to the otologist. The external tissues may become involved by suppuration extending outward; the cranial contents, including nerves and vessels, by an extension of the disease in this direction.
I shall devote attention to the spread of edema from mastoiditis to these various aspects of the temporal bone, its clinical location and its significance as regards diagnosis and prognosis. To further this end the anatomy of the external soft structures over the mastoid process must be reviewed.
Depending on the conformation of the mastoid process (i.e., whether it is cancellous or sclerotic) and the texture of the tissues in juxtaposition, mastoiditis may produce peripheral edema in one of the following ways:In direct association and contiguity with the focus of suppuration. This is seen when mastoiditis occurs in a cancellous